ECUTune Stage III twin screw supercharger sign up - Page 11

oab_au · #**151** 07-05-2005, 09:13 PM

Quote:

Originally Posted by longassname

You're asking if detonation is a problem at high load and low rpms? That's an interesting question. As far as load in the usual sense of how much air is injested is concerned with the blower 9 lbs is 9 lbs is 9 lbs no matter what the mechanical load placed on the crankshaft is. Now would a higher mechanical load increase the likelyhood of detonation? I don't know, you think?

I am thinking the time that the pressure is held confined, in the combustion chamber at low engine speeds. Will timing retard alone, prevent detonation. In the auto the rpms will allways jump up to stall speed, but a manual may be held from say 1500 to 2500 rpms for a longer time. I guess the dyno is the only way to find out.

Harvey.

Duckie · #**152** 07-05-2005, 10:41 PM

I will take the one on the left in your last pic. Yay for me being able to call that one "mine" =)

longassname · #**153** 07-06-2005, 02:36 PM

Probably not even, would need a manual transmission to find out.

Quote:

Originally Posted by oab_au

I am thinking the time that the pressure is held confined, in the combustion chamber at low engine speeds. Will timing retard alone, prevent detonation. In the auto the rpms will allways jump up to stall speed, but a manual may be held from say 1500 to 2500 rpms for a longer time. I guess the dyno is the only way to find out.

Harvey.

longassname · #**154** 07-06-2005, 02:46 PM

Quote:

Originally Posted by tomssvx

I stripped my manifold before sending it. I dunno about everyone else.

Tom

Tom,

Speeking of which, when you send the fuel lines and ac idler please send the butterly (iris) too. I'm going use it to make the bypass valve and make it part of the manifold.

oab_au · #**155** 07-06-2005, 08:39 PM

Quote:

Originally Posted by longassname

Tom,

Speeking of which, when you send the fuel lines and ac idler please send the butterly (iris) too. I'm going use it to make the bypass valve and make it part of the manifold.

A by-pass valve is what I was hinting at Michael. There has to be a point at which the boost is too much for the low speed of the engine. Not only for the combustion, but for the bearings. High pressure at low speeds will rattle the bigends, the pressure rise, to crank movement would be too high. A bit like adding too much Nos at low speeds. A by-pass valve would by required to limit the boost down low. This would be more so with a manual trans. The large amount of low speeed torque that the supercharger provides, makes it very tempting to lug the engine down at these rpms. No problem with an auto, it will allways change the ratio to pick up the rpms to a normal level. but a manual would be a different story.

Not that I see a manual clutch or box, living very long behind the sort of torque that is advailable.

Harvey.

longassname · #**156** 07-06-2005, 08:44 PM

oh, ya we're already running a bypass valve. I'm just going to incorporate it into the manifold instead of using an external one now.

Quote:

Originally Posted by oab_au

A by-pass valve is what I was hinting at Michael. There has to be a point at which the boost is too much for the low speed of the engine. Not only for the combustion, but for the bearings. High pressure at low speeds will rattle the bigends, the pressure rise, to crank movement would be too high. A bit like adding too much Nos at low speeds. A by-pass valve would by required to limit the boost down low. This would be more so with a manual trans. The large amount of low speeed torque that the supercharger provides, makes it very tempting to lug the engine down at these rpms. No problem with an auto, it will allways change the ratio to pick up the rpms to a normal level. but a manual would be a different story.

Not that I see a manual clutch or box, living very long behind the sort of torque that is advailable.

Harvey.

TomsSVX · #**157** 07-06-2005, 08:45 PM

I already shipped those out last week. If u need the iris valves, i have 2 of them. let me know what u need

Tom

longassname · #**158** 07-06-2005, 08:49 PM

Quote:

Originally Posted by tomssvx

I already shipped those out last week. If u need the iris valves, i have 2 of them. let me know what u need

Tom

Ya, i could use the iris valves, thanks.

TomsSVX · #**159** 07-06-2005, 08:49 PM

cool, I will ship them tomorrow if I have time

Tom

longassname · #**160** 07-07-2005, 05:15 PM

fantastic, here comes dennis..........

http://www.nhc.noaa.gov/refresh/grap...500.shtml?3day

BigBlueSVX · #**161** 07-07-2005, 06:43 PM

Quote:

Originally Posted by longassname

fantastic, here comes dennis..........

http://www.nhc.noaa.gov/refresh/grap...500.shtml?3day

me? I'm not going to florida!

longassname · #**162** 07-08-2005, 11:18 AM

Nice, we're out of the cone of where the eye may go on this one. It looks like it should stay far enough off shore that we'll only get tropical storm winds here. A very good thing as the corner we'd be getting hit by is where the tornados would spawn.

I made the measurements to determine what size drive snouts to order for the new design and we've got the drive snouts on order.

I'm sitting down now to scan the flanges of the supercharger so i can make drawings for templates of the flanges for the manifold.

longassname · #**163** 07-08-2005, 04:07 PM

Here's the template for the intake flange. We got the bearings for the pulleys in today too.

Duckie · #**164** 07-08-2005, 09:06 PM

*explodes* Oh man, I can't wait.

longassname · #**165** 07-13-2005, 03:24 PM

I've been busy the last few days getting caught up on some of the non fabrication work. I tried some smaller pulleys to see how the engine would handle more pressure at the stock compression and which would be most effective in staving off detonation between afr and ignition timing.

The stock engine definitely does not want any more boost. There is no actual detonation or even pinging for that matter thanks to the excellent knock correction capabilities of the ECU; however, performance actually goes down instead of up--way down. It doesn't seem to be temperature related either. It seems to be strictly pressure that makes the difference so I'm afraid people who hope to run high boost intercooled turbo setups on the stock eg33 are going to be out of luck. Of course for us we are going to see huge power gains because we are using a positive displacement blower and seeing the massive low end increases.

Putting a pulley on that increased pressure beyond what the engine was happy with effected the lower rpms the worst. I first modified the fuel to see the effect of richening the afr and cooling things down. It did help but not enough to correct things. First I richened the whole fuel curve up and that helped then i went to the lower rpms and richened them up so the whole fuel curve was running about 11.5 to 1- just roughly as that was all that was needed for this experiment. That helped a little more but still not dramatically fixing anything.

I then took out 5 degrees of timing accross the board and that helped quite a bit more than richening the afr. It still didn't make higher boost levels perform well but it clearly indicated that the timing inefficiencies were caused by pressure and not temperature. This was further bared out by plotting the blower output with the various pulleys on the compressor map. The abiatic efficiency was higher at the higher boost levels and the temperature difference wasn't very big--certainly less than we were cooling things down with the extra fuel.